Posted
by
Soulskill
on Saturday September 29, 2012 @06:30PM
from the also-may-not dept.

cylonlover writes "Titan is Saturn's largest moon, and it's said to be one of the most Earth-like celestial bodies in the Solar System. It has a thick atmosphere, and is covered with a network of seas, lakes and rivers – albeit ones made up of liquid hydrocarbons instead of water. Now, a team of scientists are proposing sending a boat-like probe to Titan, that would travel across its largest lake. The probe, which is still in the concept stage, is known as TALISE – that stands for Titan Lake In-situ Sampling Propelled Explorer, although it's also an Iroquois word for 'beautiful water.' The plan calls for it to land in the middle of Ligeia Mare, which is near the moon's north pole. It would then set out on a six-month to one-year mission, taking scientific measurements and obtaining samples as it makes its way to the closest shore."

The previous proposed Titan floater mission (TiME) was rejected last month by NASA. Since this different design is being developed in Europe, I would assume they would pitch the idea to the ESA. There are two big problems: 1) the ESA doesn't have experience with RTGs and 2) the ESA doesn't have experience sending and controlling spacecraft to the outer planets. The best that they have done is the Huygens drop probe that was attached to Cassini and the ESA contribution to Ulysses. It is doable, but it would be extremely expensive since there is no in-house experience. Roskosmos isn't an option since they, like the ESA, have no RTG or outer planet exploration experience.

Only a NASA partnership could get this done with a reasonable budget and NASA doesn't want to do it. In my opinion, this design is nice, but it isn't going to happen unless NASA gets a big budget boost.

Plenty of things do fine without solar, nuclear, or air. The obvious example is the Space Shuttle, using fuel cells. Swedish submarines use cryogenic liquid oxygen with diesel fuel to heat a Stirling engine. German submarines use hydrogen fuel cells.

If you wanted to bet that the lake really is liquid methane/ethane, you could just bring an oxidizer. You could even run a very fuel-rich piston engine.

Non-RTG nuclear is also possible. You have an entire lake of cooling fluid. You can use it as cooling for a tr

You're getting greedy. Make do with less. Each moment on the surface is less valuable than the preceeding moment. An hour on the surface, without even moving, is pretty damn useful. It probably gets you 90% of the value of spending a year roving around.

Oh God am I depressed that NASA's TiME mission didn't get funded! It would have been ten times cooler than the mission they ended up with. Discovery class missions were meant to be riskier than other larger classes of missions. But as the Discovery mission starts get fewer and fewer, inevitably the tolerance to risk goes down.

Icebergs exist because of a property of water that is somewhat unique, where the solid form has a lower density than the liquid form. That is exaggerated even further with water because the "solid" water (Arctic ice sheets as well as calving from glaciers) is generally free of salt but the salt concentration in liquid water tends to have an even higher density than ordinary fresh water... giving additional buoyancy thus letting those "icebergs" float in the liquid of the oceans on the Earth.

Good question. The answer might have something to do with pressure. If you're curious, you have some interesting reading in store. Another question: why would we want to explore there? That can get even more interesting.

Probably doesn't help that the bottom of the ocean in a lot of places is covered in silk and organic material that would be really difficult to rove over. As far as autonomous submersibles, there is a lot of work going on with those. The problem is they would need to last a long time or be really cheap. Otherwise, they face competition from other observation methods, like buoys and remote controlled submersibles. It is kind of like asking why don't we have autonomous rovers on land either, where we are

It turns out to be really hard to comunicate with stuff on the bottom of the ocean. Salt water absorbs RF like crazy at useful frequencies. ULF works but has an abysmal data rate. This means you either hang your submersible on a tether or let it go black and operate fully independently for long periods and surface to report back.There are a ton of unmanned craft using both methods.

The Europe-built Huygens probe that landed on Titan a few years ago was designed to float in case it had landed on liquid (solid land by luck of the draw). However, it only was designed for a very limited life-time in order to keep it small.

That's based on a rather narrow and specific definition of what it means to be "earth-like". In human terms, there are many other bodies on the solar system on which we (and any other kind of life as we know it) could live on far easier than Titan.

Titan is the only other place in the Solar System that we know of with an active hydrological system of rivers, channels, rain, and active erosion from that liquid. While not a perfect analogy to the Earth, the mere fact that some other place in the universe that we can also get to with existing technology exists is plenty of reason for going there alone. That a second hydrological system can be used for comparison enables all sorts of scientific theories to be tested simply because it allows for comparis

Exactly what I was going to post but I checked first somebody else wouldn't be puzzled as well
I think we should create the Association For Removal Of Broken Acronyms (AZRABOA) which also means 'WTF ??' in ancient Klingon

I suppose not every goal is finding extra-terrestrial life, but I almost feel like this is missing the real opportunity on Titan. This is a planet with both lakes of hydrocarbons and volcanic activity, theoretically perfect for life (admittedly neglecting H_2O). Surely a submarine would be more useful than a boat? Wouldn't we rather explore the depths and try to find primitive life where it is most likely to be created (by my admittedly limited understanding of abiogenesis theories)?

The amount and type of power needed for a sub might pose a problem without something on the surface. Perhaps the first priority might be to get there and see how long we can last, then use the boat as a relay for communications or something.

Maybe one day, but a boat is much easier to build and send to another planet than a submersible is. All a boat requires is a film and lighter-than-hydrocarbon gas, while a submersible requires pressure/liquid proofing, some ability to maintain neutral buoyancy, and some way to transmit information back through a medium thicker than the atmosphere.

I am still waiting for a Europa ocean-going mission. That's the best chance of finding other life in the solar system. We need some sort of easy way to melt through the ice layer, though. (Maybe slowly, though radioactivity?). I suppose that would make the probe more of a submarine than a boat though.

One of my pet hates is that when the media publishes a measurement, they will give both metric and imperial, and will calculate it to ridiculous significant figures.

For instance, this imaginary robot might weigh, you know, round about 100 kilo - which is 220.5 lbs! Yep, they know know the measurements to the nearest 10th of a pound, but coincidentally it happens to be a really round figure in metric terms.

I agree that uncalled for rounding when doing unit conversions in popular media articles is something that needs to be mentioned and criticized. The point is that the author is attempting to give a comparison for people unfamiliar with the other measurement unit into something they are familiar. They should stick with a couple digits of accuracy and get the correct order of magnitude.

Would they do the same thing if they were trying to convert the price of somet

A Duck being a craft that goes on land and liquid.
Where a body of water may be interesting, One should
not pass up the ability to go ashore. If the Atmosphere
will support it a balloon hover craft would access
both land and ocean.